[clear-browsing-data] Change history string for 'sync is paused' state

When sync is paused, the string for the history checkbox is changed from
"Clears history and autocompletions in the address bar. Your account may
have other forms of browsing history at myactivity.google.com."
to "Clears history and autocompletions in the address bar."

Bug: 893696
Change-Id: I1aba27b8902b39bc2e28e8e66e564a58327fcc33
Reviewed-on: https://chromium-review.googlesource.com/c/1280672Reviewed-by: Scott Chen <scottchen@chromium.org>
Commit-Queue: Thomas Tangl <tangltom@chromium.org>
Cr-Commit-Position: refs/heads/master@{#599712}

chrome/browser/resources/settings/clear_browsing_data_dialog/clear_browsing_data_dialog.js

@@ -258,7 +258,7 @@ Polymer({
       historySummarySignedIn, historySummarySynced) {
     if (isSyncingHistory && !hasSyncError) {
       return historySummarySynced;
-    } else if (isSignedIn) {
+    } else if (isSignedIn && !this.isSyncPaused_) {
       return historySummarySignedIn;
     }
     return historySummary;